Taking Too Much of This 1 Gut Health Supplement Could Backfire—Here’s Why

Probiotics, aka the good bacteria that thrive in your digestive tract, have skyrocketed as a go-to supplement for gut health in recent years. Whether you're looking to ease bloating, improve digestion, or support your immune system, these supplements (along with the foods rich in these live active cultures, like yogurt) promise a range of benefits. But...is it possible to take too many probiotics?

Like with any supplement, finding the right dosage is key, says C. Vivek Lal, MD, a neonatal physician, director at Heersink Institute of Biomedical Innovation at University of Alabama Birmingham, and founder and CEO of ResBiotic Nutrition, Inc. But your reason for taking probiotics, and the strains you reach for, will likely determine how much you should take daily.

Here’s a breakdown of whether probiotics are right for you and how to determine the right dosage—and strain—for your health needs.

First, what are probiotics?

Probiotics are live microorganisms, otherwise referred to as "good bacteria," that help maintain the overall balance of bacteria in your gut (called your microbiome¹). Maintaining the amounts of both good and bad bacteria in your digestive tract is helpful not only for the state of your gut, but also your overall well-being.

“Probiotics are vital in maintaining gut health by supporting microbial balance, but their influence extends far beyond digestion,” says Dr. Lal. “They enhance nutrient absorption and produce beneficial metabolites (a substance produced during metabolism) that interact across the Gut-X axis²—a powerful connection between the gut and key organs like the lungs, heart, and metabolism.”

“Additionally, we know that the gut plays a large role in our immune system,” says Gina Wideroff, MD, a board-certified gastroenterologist with Gastro Health. This means that probiotics, and supporting a healthy gut microbiome, could help boost your immune system to protect your body against germs and certain viral illnesses, she adds.

While these good bacteria are naturally present in your body, you can get more of them by eating fermented foods like yogurt, kimchi, and kombucha, which contain high amounts of live active cultures of probiotics in various strains.

Plus, as we know, probiotics also come in supplement form. You can purchase them in capsules or gummies at most pharmacies or health food stores, and most are advertised to target a specific health concern, such as constipation or bloating.

Can you take too many probiotics?

Though probiotics are typically safe if you have no serious underlying health conditions, Dr. Lal says it is possible to overdo it. "Excessive amounts or lower-quality products can sometimes overwhelm the gut microbiome, leading to temporary digestive discomfort," he adds. "The key is balance: probiotics should be tailored to individual needs rather than taken in excess."

All that to say, taking too many probiotic supplements at once can cause digestive upset³. It's not necessarily dangerous, but could make you feel a little uncomfortable. This is why it's important to consult with your healthcare provider about trying supplements before taking them, to make sure they're right for you.

Both Drs. Lal and Wideroff say minor side effects should fade over time as your gut adjusts to a daily probiotic supplement, especially if you're taking the proper dose. In the meantime, you may notice symptoms like:

• Gas
• Bloating
• Diarrhea
• Cramps
• Abdominal discomfort

But probiotics aren’t for everyone. “Those with weakened immune systems—like people undergoing chemotherapy, organ transplant recipients, or those with severe illnesses—should consult a doctor first,” says Dr. Lal. “Individuals with severe gut dysbiosis⁴ (i.e., bacterial imbalance), small intestinal bacterial overgrowth (SIBO), or histamine intolerance⁵ (the inability to metabolize histamine) may react poorly to certain strains and need a more tailored approach," he adds.

The reason why? Supplements that have not been third-party tested for quality assurance may contain ingredients (like harmful microbes) that could worsen preexisting complications like infection or bacteria entering the bloodstream. So, if you have a stomach infection, for instance, you might not want to take probiotics because it could exasperate the issue. This is also why it's not advised to give probiotic supplements to preterm infants, as it could increase the risk of infection.

So, how much probiotics should you take?

Before diving right into taking a probiotic capsule every morning with breakfast and other vitamins, it's important to consider whether you actually need probiotics in the first place.

Start by talking with your healthcare provider about why you want to try them. Maybe you're taking an antibiotic⁶ (which tends to kill both good and bad bacteria) and want to support your gut microbiome at the same time, or you have chronic constipation that you'd like to regulate—all good reasons to want to give probiotics a whirl. If your provider gives you the "okay," they'll likely recommend a product with at least 1 billion colony-forming units (CFUs), though for context, some products contain up to 50 billion CFUs per dose.

"There isn’t a one-size-fits-all dosage for probiotics, as the optimal amount depends on the strain, your health status, intended benefits, and clinical trials that prove the dose response," says Dr. Lal. Meaning, the most effective probiotic for you may not be the best option for someone else.

“Consumers should make a habit of reading the product labels and the science behind individual strains of probiotics used in the products,” says Dr. Lal. “For example, several strains of Lactobacillus have been studied to provide gut benefits, but only specific lactobacilli RSB⁷ strains offer lung benefits.”

That said, certain probiotic strains have been linked to specific benefits. Here's a breakdown of the most common ones:

• For bloating: Both Lactobacillus and Bifidobacterium have shown promising results⁸ against abdominal bloating.
• For constipation: Bifidobacterium lactis and Lactobacillus casei Shirota have been linked to increased bowel movements⁹ and an improvement in constipation symptoms.
• For diarrhea: The NIH says research links Saccharomyces boulardii to reduced diarrhea in children, and Lactobacillus rhamnosus GG to a reduced risk for antibiotic-associated diarrhea.
• For irritable bowel syndrome (IBS): A review in the Journal of Gastroenterology and Hepatology found that Lactobacillus and Bifidobacterium can help balance your gut¹⁰ to relieve symptoms of IBS.

Ultimately, your healthcare provider can help you figure out which strain is best for you based on your needs. And keep in mind: the Food and Drug Administration (FDA) does not regulate supplements, including probiotics, so make sure you are choosing an expert-approved, high-quality product that has been tested by an organization such as the United States Pharmacopeia (USP) or the Public Health and Safety Organization (NSF).

When to see a healthcare provider

Bottom line? Probiotics can be a helpful resource for regulating your bowels and keeping your immune system strong, but yes, it is possible to take too many of them. That's why it's important to check in with your healthcare provider before giving them a try, to make sure they're right for you.

If you're an overall healthy person, a large dose of probiotics won't necessarily cause lasting harm, but it could cause uncomfortable side effects like stomach pain, bloating, and diarrhea. Even if you take your provider's recommended dose, you could still experience mild effects as your body adjusts to the supplement, though these should go away over time.

However, if they don't go away, both Dr. Lal and Dr. Wideroff recommend seeing your healthcare provider ASAP, especially if your symptoms are severe or last longer than two weeks (despite lowering your dose and adjusting your diet). Be on the lookout for symptoms like:

• Unexplained weight loss
• Blood in your stool
• Severe abdominal pain
• Fever
• Severe, constant bloating that causes significant discomfort
• Chronic, watery, or frequently occurring diarrhea
• Heartburn
• Difficulty or pain with swallowing

These could point to a more serious gastrointestinal disorder that needs to be properly treated with medication and other lifestyle changes, and you may need to stop taking probiotics altogether.